The background of the invention will be set forth in two parts.
1. Field of the Invention
This invention relates to industrial conveyors and more particularly to devices for cleaning moving continuous conveyor belts.
2. Description of the Prior Art
The problem of keeping a moving continuous conveyor belt clean has been present for as long as such devices have been in use. Patents have been issued and many articles published in trade journals on this subject, even before the turn of the century.
By far, the most popular mechanism is a rotating brush mounted below a continuously moving conveyor belt. The bristles of the brush are radially mounted on a brush drum having an axis of rotation parallel to the plane of the conveyor belt but perpendicular to the direction of belt travel. The drum is usually directly driven by an electric motor or belt-driven by a separate motor or by the mechanism that causes the belt to move. The brush sweeps the surface of the belt and generally rotates in a direction to cause the brush bristles to move in a direction opposite to that of the conveyor belt.
The bristles of this type of brush are usually closely spaced and tend to easily collect particles between adjacent bristles and thereby lose much of their cleaning effectiveness. In order to reduce this problem, some prior art mechanisms include what is known as a "flicker bar" which has an elongated blade mounted parallel to the axis of the rotating brush and positioned to just contact the bristle ends in order to "flick" the bristles and dislodge trapped particles and prevent "loading".
Another approach used in solving the problem of removing foreign particles adhering to the surface of a conveyor belt is to utilize a belt cleaner having a series of resilient conical discs mounted on a rotating shaft, the shaft being mounted adjacent and parallel to the belt surface. Particles so removed from the belt tend to be deflected toward and adjacent conical brush segment and means must be provided to prevent a transfer of particles between such conical segments.
More recently, the more or less solid rotating brush configuration has been replaced by a plurality of spaced, helically shaped brush strips mounted on a rotating hub that has an axis parallel to the plane of the conveyor belt. The spacing between the strips helps reduce the loading problem, but in common with the previously mentioned conveyor belt cleaning techniques known to the prior art, this scheme suffers severly from wear and relatively high replacement cost. It should, therefore, be evident that a simple and effective mechanism to clean moving conveyor belts that avoids a tendancy to load and has superior longevity would constitute a significant advancement in the art.